Twenty-one year old Emily Cummins started inventing products at the tender age of four, when she received a hammer for a gift - and she hasn't stopped since.

Her latest invention, already being used by hundreds of famiilies in Africa, is an affordable solar powered refrigerator, built entirely from ordinary household items.

Emily, who came up with the idea while working on a school project, got her inspiration by researching how our ancestors used to keep things cool.

Operating on the simple principal of evaporation, the refrigerator comprises of two cylinders. The inner cylinder is made of metal, while the larger, outer cylinder, into which holes are drilled, can be either plastic or wood. The space between the two containers is filled with material that retains water - like sand, soil or wool.

As the sun heats up the cylinder, the water evaporates. Since the water-soaked material is sticking close to the inner cylinder, it draws away the heat from the sides, keeping the inside of the cylinder at a cool 6-degrees - perfect for storing perishable products like meat and milk.

After coming up with the concept, Emily, who lives in Keighley, West Yorkshire spent five months perfecting and demonstrating her invention to the people of Namibia , who affectionately refer to her as 'Fridge Lady'. Besides this, Emily's other award winning inventions include a toothpaste squeezer for people suffering from arthritis and a water-carrier for the third world.

Now on her way to college for a business degree, Emily's next mission is to make a more sophisticated version of her refrigerator, for use in medical emergencies.